An apparatus is described that includes a plurality of queuing paths. The context map comprises a visible image representing a location of the unmagnified region that is being magnified. The module has a communications path between the controller and the enclosure connector by which the controller can communicate with storage devices in the enclosure. For DMOS transistors, this achieves high breakthrough voltages even with low turn-on resistances, and reduces the space requirement, in particular with regard to driver structures. At least one of the fixed contacts has first and second inter-connected parts bearing resiliently against the first and second rotor surfaces respectively for contact with the corresponding fist and second moving contact parts according to the angular position of the rotor.